org.apache.webbeans.intercept

Class InterceptorHandler

java.lang.Object

org.apache.webbeans.intercept.InterceptorHandler

All Implemented Interfaces:

Serializable, InvocationHandler, javassist.util.proxy.MethodHandler

Direct Known Subclasses:

DependentScopedBeanInterceptorHandler, NormalScopedBeanInterceptorHandler

public abstract class InterceptorHandler
extends Object
implements InvocationHandler, MethodHandler, Serializable

Logic for how interceptors & decorators work in OWB.

• 1- Configuration of decorators and interceptors

  Decorators and Interceptors are configured from BeansDeployer class via methods defineManagedBean(class) and Those methods further call defineInterceptor(interceptor class) and defineDecorator(decorator class) methods. Those methods finally call WebBeansUtil.defineInterceptor(org.apache.webbeans.component.creation.ManagedBeanCreatorImpl, javax.enterprise.inject.spi.ProcessInjectionTarget) and WebBeansUtil.defineDecorator(org.apache.webbeans.component.creation.ManagedBeanCreatorImpl, javax.enterprise.inject.spi.ProcessInjectionTarget) methods for actual configuration.

  Let's look at the "WebBeansUtil's" methods;

  • defineInterceptor : This method firstly creates a "Managed Bean" for the given interceptor with "WebBeansType.INTERCEPTOR" as a type. After checking some controls, it calls "WebBeansInterceptorConfig#configureInterceptorClass". "configureInterceptorClass" method creates a "WebBeansInterceptor" instance that wraps the given managed bean instance and configuring interceptor's *Interceptor Binding* annotations. If everything goes well, it adds interceptor instance into the "BeanManager" interceptor list.
  • defineDecorator : Exactly doing same thing as "defineInterceptor". If everything goes well, it adds decorator instance into the "BeanManager" decorator list.

• 2* Configuring ManagedBean Instance Interceptor and Decorator Stack

  Currently interceptors and decorators are supported for the "Managed Beans". OWB delegates calling of "EJB Beans" interceptors to the EJB container. It does not provide built-in interceptor and decorator support for EJB beans. Current implementation supports configuration of the interceptors on the "Managed Beans" with 2 different scenarios, i.e. it supports "EJB related interceptors ( defined by EJB specification)" and "JSR-299 related interceptors (defined by interceptor bindings)". Managed Beans interceptor and decorator stacks are configured after they are instantiated by the container first time. This method can be found in the AbstractInjectionTargetBean" class "afterConstructor()" method. Actual configuration is done by the (org.apache.webbeans.component.AbstractInjectionTargetBean) and DefinitionUtil.defineDecoratorStack(org.apache.webbeans.component.AbstractInjectionTargetBean<?>). In "DefinitionUtil.defineBeanInterceptorStack", firstly it configures "EJB spec. interceptors" after that configures "JSR-299 spec. interceptors." In "DefinitionUtil.defineDecoratorStack", it configures decorator stack. "EJBInterceptorConfig" class is responsible for finding all interceptors for given managed bean class according to the EJB Specification. (But as you said, it may not include AroundInvoke/PostConstruct etc. disablement scenario!). "WebBeansInterceptorConfig" class is responsible for finding all interceptors for a given managed bean class according to the "JSR-299, spec." It adds all interceptors into the bean's interceptor stack. It first adds "EJB" related interceptors, after that adds "JSR-299" related interceptors. For "JSR-299" related interceptors, it orders the interceptors according to the "InterceptorComparator". Basically, it puts interceptors in order according to how they are ordered in a "beans.xml" configuration file. Similarly, it configures managed bean's decorator stack according to the decorator resolution rules. Also, it orders decorators according to the "beans.xml" configuration file that contains decorator declarations.

• 3* Invocation of Interceptors and Decorators

  Invocation is handled by the "InterceptorHandler" class (It has an absurd name, it can be changed to a more meaningful name :)). It works nearly same as what you have explained. First of all, it checks that calling method is a business method of a managed bean or not. After that it filters interceptor stack for calling method (Current design of filtering may not be optimal!). Firstly it adds EJB interceptor to the list and then adds JSR-299 interceptors. After that, it starts to call all interceptors in order. After consuming all interceptors it calls decorators. (as you explained, seems that the logic may not be correct here. Currently, interceptors and decorators are not related with each other. They are called independently).This must be changed!.

Version:

$Rev: 1426744 $ $Date: 2012-12-29 12:22:44 +0100 (Sat, 29 Dec 2012) $

See Also:

WebBeansInterceptorConfig, WebBeansDecoratorConfig, WebBeansInterceptor, WebBeansDecorator, EJBInterceptorConfig, Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected OwbBean<?>	bean Proxied bean
protected Map<Method,List<InterceptorData>>	interceptedMethodMap Intercepted methods
protected WebBeansContext	webBeansContext

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	InterceptorHandler(OwbBean<?> bean) Creates a new handler.

Method Summary

Methods

Modifier and Type	Method and Description
protected abstract Object	callAroundInvokes(Method interceptedMethod, Object[] arguments, List<InterceptorData> stack) Call around invoke method of the given bean on calling interceptedMethod.
protected BeanManagerImpl	getBeanManager()
Object	invoke(Object instance, Method method, Method proceed, Object[] arguments, CreationalContextImpl<?> ownerCreationalContext) Calls decorators and interceptors and actual bean method.
Object	invoke(Object instance, Method method, Object[] arguments, CreationalContextImpl<?> ownerCreationalContext)
protected boolean	isNotInterceptedOrDecoratedMethod(Method method) This method provides a way to implement a negative cache for methods which are known to become intercepted or decorated.
protected void	setNotInterceptedOrDecoratedMethod(Method method) This method will get called after the interceptorStack got evaluated and we found out that it isnt intercepted nor decorated.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface javassist.util.proxy.MethodHandler

invoke

Methods inherited from interface java.lang.reflect.InvocationHandler

invoke

Field Detail

bean

protected OwbBean<?> bean

Proxied bean

interceptedMethodMap

protected transient volatile Map<Method,List<InterceptorData>> interceptedMethodMap

Intercepted methods

webBeansContext

protected WebBeansContext webBeansContext

Constructor Detail

InterceptorHandler

protected InterceptorHandler(OwbBean<?> bean)

Creates a new handler.

Parameters:

bean - proxied bean

Method Detail

isNotInterceptedOrDecoratedMethod

protected boolean isNotInterceptedOrDecoratedMethod(Method method)

This method provides a way to implement a negative cache for methods which are known to become intercepted or decorated. This is useful since the calculation actually takes a lot of time.

Parameters:

method - which should get invoked

Returns:

true if the method is known to not get intercepted, false we dont know or it gets intercepted

See Also:

setNotInterceptedOrDecoratedMethod(java.lang.reflect.Method)

setNotInterceptedOrDecoratedMethod

protected void setNotInterceptedOrDecoratedMethod(Method method)

This method will get called after the interceptorStack got evaluated and we found out that it isnt intercepted nor decorated. The information might get cache to skip the evaluation in a later invocation.

Parameters:

method -

See Also:

isNotInterceptedOrDecoratedMethod(java.lang.reflect.Method)

invoke

public Object invoke(Object instance,
            Method method,
            Method proceed,
            Object[] arguments,
            CreationalContextImpl<?> ownerCreationalContext)
              throws Exception

Calls decorators and interceptors and actual bean method.

Parameters:

instance - actual bean instance

method - business method

proceed - proceed method

arguments - method arguments

ownerCreationalContext - bean creational context

Returns:

method result

Throws:

Exception - for exception

invoke

public Object invoke(Object instance,
            Method method,
            Object[] arguments,
            CreationalContextImpl<?> ownerCreationalContext)
              throws Exception

Throws:

Exception

callAroundInvokes

protected abstract Object callAroundInvokes(Method interceptedMethod,
                       Object[] arguments,
                       List<InterceptorData> stack)
                                     throws Exception

Call around invoke method of the given bean on calling interceptedMethod.

Parameters:

interceptedMethod - intercepted bean method

arguments - method actual arguments

stack - interceptor stack

Returns:

return of method

Throws:

Exception - for any exception

getBeanManager

protected BeanManagerImpl getBeanManager()

Returns:

bean manager